I can reproduce this, across 12.2, as well as the Oct 1 monthly Gotham build.

I have a 2012 MacMini connected via HDMI to a Denon AVR, then via HDMI to a Samsung LCD.

Typically I leave XBMC running and turn off the AVR/TV when not in use. If I power up the AVR/TV (no video in progress, paused, etc.) and then try to play a new video, I almost always get the stuttering and lack of audio. Restarting XBMC fixes it every time.

I'm wondering, is the output buffer not being flushed when a video is started? Any other tips in fixing this?

I'm experiencing the same problem. Audio output device is set at default when its happening. Its very consistent at about 1 hour into any playback.
At 22:56 I started watching a movie. At 23:43 I start seeing the problem. The video becomes halted, showing one frame every 2 seconds.

There is no "default" available. Oddly if I set it to Optical/Coax I still get sound even thought that's not connected in my case.

This is pretty frustrating as I need to restart XBMC every time I turn on the TV/AMP. Stopping and starting a new video doesn't help. Each new version I try has the same issue. It seems like something's not getting reset, flushed, etc. when a new episode is played, which I think could be possible.

Can anyone provide any guidance to help me dig into the code and diagnose this? Are there known bugs, issues, etc.?

I have the same problem, normally when i pause a movie and my amplifier goes off. Put my amplifier back on, and resuming or restarting the movie will end in stutter and lost audio, restarting xbmc helps.
Sometimes the stutter goes away but the sound stays away.

If I tell my mac mini to out put the sound to my Dell monitor when im using the computer for other things, it causes xbmc video playback to take a dive.

To fix this you dont need to restart xbmc, simply make sure the mac mini is set for it's output to be whatever the xbmc is connected to. In my case, i need to tell the mac mini to output sound back through the Samsung HDMI. This is done via the system preferences - audio icon on the Mac.

Once that is done, i simply go into System options, then Audio settings in XBMC and toggle the Audio from whatever it was set to, to something else, then back to it's original setting. So in my case, it's normally set to the Optical "even though it's thunderbolt adapter to HDMI" I then change it to anything else, then right back to Optical and problem is solved.

Sometimes even when Xbmc is at idle for a while this will happen. all i do is toggle the audio settings in xbmc to something else then back to original setting and problem is solved.

I have the same issue, since running 12.2 XBMC. Not sure if it was in 12.1, but it definitely wasn't in Eden when I was running Eden on Lion. I thought maybe running 12.3 on Mavericks would fix the issue, but it didn't which is why I am posting here.

Whenever I use my Harmony remote to turn on or switch back over to the Mac mini activity, I lose HDMI sound. Subsequent play of any video results in no audio and video stuttering. XBMC is not syncing the HDMI audio correctly.

Within XBMC, I have tried setting the Audio Output Device to both HDMI and Default, neither of which fix the issue. I have also played around with setting the Audio Output to Optical rather than HDMI. Nothing changes this odd behavior. If I go in and toggle the Audio Output Device, I get sound back and this fixes the issue. Yes, it's a workaround, but, this sucks and this workaround is definitely not wife and family friendly.

Does Eden work on Mavericks? This is definitely a show-stopper. I'm surprised more people haven't mentioned this issue.